Dyeing of hardened casein



It Patented a... ize, i93

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;== DENED oAsaiN Frederick Hill ack Augustus .Radley, nmkley, England, assignors to Imperial Chemical Industries Limited, a corporation oi Great Bantam No Drawing. Application January 18, 1938, Se-

iiiggqNo. 185,624. In Great Britain January 29,

6 Claims.

The production from casein of hardened masses and articles is well known and such material is manufactured under various trade names; It finds a variety of applications ior instance, in

the making of buttons. For the polishing of hardened casein a method employed is to immerse the material in an'aqueous hypochlorite solution, e. g. of sodium or calcium hypochlorite, followed by drying. This treatment imparts to 10 the hardened casein a gloss or polish, but renders it difiicult to dye.

The dyestufis used at present are acid dyestufis. Whereas untreated hardened casein readilytakes up acid dyestufis' from an aqueous dyeis bath, casein which has been treated with hypochlorite loses much of its ainnity for such dyes; only tinct6rially weak dyeing can be obtained or it may even be that very little or no colouration of the material can be efiected. A further drawback to the use of ordinary aci dyestufis for the dyeing of formed casein articles,-

ior instance, buttons, is that uneven dyeings are liable to be produced and their rims or edges are frequently dyed a deeper shade than the remainder. r

This invention has as an object to devise a method of dyeing hardened casein which will not have the disadvantage mentioned above. A fur: ther object is to provide better dyed casein ar-- ticles. Further objects will appear hereinafter.

These objects are accomplished by the following. invention. ,We have found that we can dye hardened'casein if weemploy for the dyeing of this substancemonoazo, or anthraquinone' dyestuffs containing an oxyalkyl radicle esterified by an acid sulphuricester group, e. g.

onzcmososn l 40 or its salts, attached to anaromatic nucleus by an --O or an -N linkage but which are devoid of sulphonic or carboxylic groups attached di-" rectly to an aromatic nucleus;

The following examples illustrate but do 'not limit the invention. The parts are' by weight.

Example 1 1 part of the dye stufi p-nitraniline fi-ethyl- N-p-hydroxyethylaniline sulphuric ester is dissolved in 5000 parts of waterand 200'parts .of'a 1% formic acid solution addd.- Buttons made from casein are dyed in this solution for 10 min} utes at a temperature of 70 C. and attain a deep and level scarlet colour.

v A Example 2 1- part of the dyestufi, p-amlnophenyl-p-hydroxyethyl ether sulphuric esterp-cresol is, dissolved in 5000 parts of water and 200 parts of a 5 1% formic acid solution added. Casein buttons which have been treated with hypo'chlorite solution are dyed in this solution for 10 minutes at a temperature of C. and acquire a bright and level yellow colour. 10 i Example'.?

1 part of the dyestufi, the sodium salt of the sulphuric ester; of 1-methylamin0-4-fl-hydroxy- "ethylamino'anthfaquinone, is dissolved 'in 5000 15 parts of water and 200 parts of a 1% formic acid solution added. Thin casein slabs are dyed in this solution for 10 minutes at 70 C. and aiquire a deep and level blue colour.

1 part of the dyestuiithe sodium salt of the sulphuric ester of 1-amino l-p-hydroxyethy1am- -ino-2-methylanthraquinone is dissolved in 20,000

parts of water containing 800 parts of. a 1% 25 'iormic acid solution. Thetemperature of this solution is maintained at C. and casein buttons are immersed in it for .10 minutes, after which they are removed, rinsed in water and dried. The buttons are thus obtained coloured 30 violet. V I

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit our- 35 v selves to the specific embodiments thereof, ex-

cept as defined in the appended claims.

l. A process for the dyeing of hardened casein which comprises applyingto the material from 40 adyebath a .dyestufl of the class consisting of monoazoand anthrao uinone dvestufis which dyestufi contains ahydroxy-alkyl sulphuric ester group attached to'an aromatic nucleus through an atom of the class consisting of oxygen and nitrogen 45: I and which dyestuff isvdevoid' of any sulphonic .and carboxylic groups attached directlyto an aromatic nucleus.

2. A process according to claim 1 in which the I hardened casein has been polished by treatment 50 with an aqueous hypochlorite solution.

r i 3. A process according to-claim l in which the' .hydroxyalkyl sulphuric ester group in the v dye stuff is a sulphatoethyl group.

4. A process accordingto claim 1 in which theta Example 4 20 dyestuff employed in the dyebath is an azo dyestuff prepared by diazotizing p-nitraniline and coupling with N-ethyl-N-beta-hydrowethylamline sulphuric ester. t w

5. A process according to claim 1 in which the dyestufi employed in the dyebath is an azo dyestufi prepared by diazotizing p-aminophenylbeta-hydroxyethyl ether sulphuric ester and coupling with p-cresol. p

6. A process according to claim 1 in which the dyestufi employed in the dyebath is the sodium salt of the sulphuricester of l-methyldmino-- beta-hydroxyethyla1p1noanthmquinone.

FREDERICK HILL. JACK AUGUSTUS HADLEY. 

